This invention relates to novel hydroxy-t-alkyl peroxyesters (A) and the use of these compositions as free-radical initiators for improved vinyl monomer polymerization processes and as curing catalysts for improved unsaturated polyester resin curing processes.
From an economic standpoint the polymer industry wishes to increase production of polymeric resins without resorting to building additional expensive production facilities. It is well known in the polymerizations arts, especially in the art of polymerizing vinyl chloride, that rates of polymerizations can be enhanced by using more active free-radical catalysts; thus, polymerization cycle times can be decreased and production capacity can be increased when this technique is employed. This phenomenon is especially useful in vinyl chloride polymerizations, since more active catalysts result in higher polymerization rates without simultaneously affecting polymer molecular weight characteristics (assuming that the temperature is not changed); hence, polymer physical properties remain unchanged. It is, also, well known in the peroxide art that half-life characteristic (a measure of peroxide activity) of peroxides can be changed significantly for certain classes of peroxides by employing various structural changes in the peroxide.
The hydroxy-t-alkyl peroxyesters of the present invention have been found to improve the efficiency of polymerization systems using lesser amounts of the initiator than were used in the prior art. The 10 hour half-life temperatures of compounds of the present invention are significantly decreased over similar prior art peroxyesters.